The canine narcolepsy-cataplexy colony maintained by the Stanford University Sleep research Center provides a valuable resource for the investigation of mechanisms underlying this debilitating disease, which is known to affect humans, canines, and equines. The Stanford colony consists of severl breeds of dogs, all of which exhibit a constellation of symptoms which are in most respects identical to human symptoms of narcolepsy. The narcoleptic animals are used in a wide variety of experiments including the following: (1) Genetic studies, which have established a probable autosomal recessive mode of transmission of this disease; (2) Neuropharmacological studies, which have shown that drugs which interact with the muscarinic cholinergic system in the central nervous system are most effective in suppressing cataplexy; (3) Neurochemical studies, which have indicated tha there are abnormalities in the concentration of certain neurotransmitter substances in the brain and cerebrospinal fluids of narcoleptic animals; (4) Polysomnographic studies, which have demonstrated that cataplectic attacks resemble rapid eye movement sleep and that the structure of sleep-waling states is different from normal dogs but similar to human narcoleptic patterns. The aforementioned studies will be continued, and the following new investigations will begin: (1) Electroencephalographic studies, utilizing techniques of telemetry and computer spectral analysis; (2) Neuroanatomical studies, seeking to localize lesions of abnormal features of the brain; (3) Acetylcholine receptor studies, which will quantify the numbers and binding affinities in a number of brainstem and forebrain areas; (4) Dietry studies to determine whether the severity of symptoms can be influenced by experimental manipulation of diet.